The Search for Extraterrestrial Intelligence (SETI) has a low probability of success, but it would have a high impact if successful. Physicists Paul Davies and Robert Wagner of Arizona State University argued last year that it makes sense to widen the search to scour the Moon for possible alien artifacts. At Penn State, researchers propose the same type of searchsearch for Mars. To date, SETI has been dominated by the paradigm of seeking deliberately beamed radio messages.

The ASU team argued that Alien civilizations may have sent probes to our region of the galaxy, and that any mission to the solar system would probably have occurred a very long time ago. The lunar environment could preserve artifacts for millions of years due to the absence of erosion and plate tectonics.

Indirect evidence for extraterrestrial intelligence could come from any incontrovertible signatures of non-human Alien technology. Existing searchable databases from astronomy, biology, earth and planetary sciences all offer low-cost opportunities to seek a footprint of extraterrestrial technology. Davies and Wagner reason that the rapidly-expanding database of the photographic mapping of the Moon's surface by the Lunar Reconnaissance Orbiter (LRO) to 0.5 m resolution offers an ideal opportunity to search for ancient artifacts and has mapped a quarter of the moon's surface since mid-2009.

Among the LRO images, scientists have spotted the Apollo landing sites as well as all of the Nasa and Soviet unmanned probes, some of which were revealed only by their odd-looking shadows.Nasa has made more than 340,000 LRO images public, but that figure is expected to reach one million by the time the orbiting probe has mapped the whole lunar surface. "From these numbers, it is obvious that a manual search by a small team is hopeless," the scientists write.

The seismometer on Nasa's Apollo 12 mission detected only one impact per month from roughly grapefruit-sized meteorites within a 350km radius. According to Davies and Wagner, it could take hundreds of millions of years for an object tens of metres across to be buried by lunar soil and dust kicked up by these impacts. Software can search for strange-looking features, such as the sharp lines of solar panels, or the dust-covered contours of quarries or domed buildings. These might be visible millions of years after they were built.

Systematic scrutiny of the LRO photographic images is being routinely conducted for planetary science purposes, and this program could be expanded and outsourced at little extra cost to accommodate SETI goals, after the fashion of the SETI@home and Galaxy Zoo crowd-sourcing projects. Hundreds of thousands of pictures of the moon will be examined for telltale signs that aliens once visited our cosmic neighbourhood if plans go ahead. Online volunteers could be set task of spotting alien technology, evidence of mining and rubbish heaps in moon images.

Elswhere, two researchers at Penn State, are asking "why have we never found evidence of other civilizations in Solar System?" The team is approached the problem mathematically, which shows that we have not looked in enough places to ensure that no extraterrestrial artifacts exist in our solar system.

Even without actual contact, like us, other civilizations could be sending unpiloted probes to quietly peek at our civilization. These probes, like ours, would be small and might be hidden in a variety of places. In the asteroid belt they would probably go unnoticed, especially if these nonterrestrial objects are only 3 to 33 feet in size, weighing little more than a ton similar to our Voyager craft.

"Extraterrestrial artifacts may exist in the solar system without our knowledge simply because we have not yet searched sufficiently," said Haqq-Misra and Kopparapu. "Few if any of the attempts would be capable of detecting a 1 to 10 meter (3 to 33 foot) probe."

Haqq-Misra and Kopparapu use a probabilistic method to determine if we have looked closely enough anywhere in the solar system to definitively say there are no nonterrestrial objects here. The analysis is based on answering the question, how sure can we be that we should have already found any nonterrestrial objects lurking in the solar system.

They view the solar system as a fixed volume and figure out the percentages of that volume that would need to be thoroughly searched using a discovery capability small enough to detect these probes, assuming that the probes are not consciously camouflaged. The researchers note that most searches to date have not been fine enough to locate such small probes or to totally rule out anywhere.

After taking into account a variety of potential biases, such as "the universe is teeming with life" or "life is rare," the team developed an equation that can be applied to a portion of the volume of the solar system and determine whether sufficient searching has been done to ensure that we can say there are no nonterrestrial objects within that volume.

"The surface of the Earth is one of the few places in the solar system that has been almost completely examined at a spatial resolution of less than 3 feet," said Haqq-Misra and Kopparapu.

But even as humans have spread across the solid surfaces of the Earth, there are still caves, jungles and deserts as well as the ocean floor and subsurface areas that have not been explored. Even with this, the Earth does have a high confidence that no nonterrestrial artifacts exist.

The moon and Mars have been searched to a small extent. An ongoing mapping project, the Lunar Reconnaissance Orbiter, is looking at the moon at a resolution of about 20 inches, so we may eventually be able to determine if there are no nonterrestrial objects on the moon. The researchers caution that surface maps may not be sufficient to distinguish between a space probe and a rock.

The surface of Mars is still mostly unsurveyed and the researchers' confidence in the probability of no nonterrestrial artifacts is low. Similarly, locations like the Earth-moon Lagrange points, the asteroid belt and the Kuiper belt might also shelter extra solar system probes, but the vast majority of the solar system's volume is uninvestigated.

"Searches to date of the solar system are sufficiently incomplete that we cannot rule out the possibility that nonterrestrial artifacts are present and may even be observing us," said Haqq-Misra and Kopparapu. They add that "the completeness of our search for nonterrestrial objects will inevitably increase as we continue to explore the moon, Mars and other nearby regions of space."

The infrared images of Mars at the top of the page show both reflected sunlight and heat radiation. The left one is taken in the near-IR and Mars looks a lot like the eye would see it, with the south pole clearly visible as well as continents. The thermal (heat) image to the right is taken in the so-called M band and clearly shows cold and warm regions on Mars.

To launch the video click on the Start Arrow. Our thanks for your support! It allows us to bring you the news daily about the discoveries, people and events changing our planet and our knowledge of the Universe.

Comments

The moon artifacts have already been discovered. There are many photos in the NASA archives that have objects airbrushed out...if it was just rocks on the lunar surface, why the need for airbrushing?
I spoke with a NASA employee at a party once. I told her about the airbrushed objects and she stated they were probably covering natural formations. I asked her why they would feel the need to do this, she said to protect the public. Protect them from what, a rock?!?
Her logic was flawed, but it just goes to show how brainwashed their employees are.

This is eerily similar to an argument in favor of 'ancient astronauts'. However, what is clear is that there have been a sizable number of as-yet unexplained things that have popped up during our exploration of space. Things that were sighted during manned missions , and other things seen by astronomers, such as flashed of light seen in craters of the moon and what appear to be clouds there as well. Much is left to be explained which, alas, is ignored. The US government has been adamant about the non-existence of UFOs, yet people keep seeing something, over and over. They have been seen for centuries, so if not UFOs, what keeps being seen? What is responsible for the phenomenon? Denial will not make it go away.

Well this article really hit home for me the scope of true understanding of whether we are definitely alone or not. Simple fact is we have not definitively searched but a small fraction of our solar system. Is is possible that we have already found evidence of advanced civilization on Mars? See for yourself: https://www.facebook.com/media/set/?set=a.361075703949087.83300.360821130641211&type=3&l=c5e42fed13

Alas, those airbrushings of the Moon might be of things disastrous to public relations but highly likely to occur-such as rock formations in the shape of too-human generative organs-and also to conceal Russian stuff (and disasters) up there. I remember hearing there were several frozen Russian cadavers up there, due to cheapass Russian tech. I don't think NASA would want either thing to have to be explained to the public.

OK What about some clear evidences on Earth's history? I am not touching ancient-astronauts theory yet, but apparently most of the historic monuments of ancient civilizations and their knowledge of cosmos and solar system are unexplainable!
On the other hand, advanced civilizations must behave as untraceable as possible to protect their own existence; and they will never knock on our doors with radio or other mediums unless they know us very well. This classic point-of-view as having Columbus-like alien explorers is not even logical. A million years of civilization at any planet (if we took the earth-like planets model as an example) will not show its face just like that. If I were an alien who could travel that distance; I would have the ability to sneak among humans and even talk to them in daylight.
If you want to find an alien, think like an alien (unfortunately we need more time to do so).

Lets start with UFOs. What people are seeing is probably American or Russian craft. ..what better way for the government to cover up our technology.
With a story of UFOs. Why cover up technology you ask? Think about it this way. If the entire world had the technology to travel at say 8000 MPH or faster .... what would happen to world security .. ( national security) would not take long for it to break down. I would think its a national threat for enemies of the. State to have such great speed .... the world is not ready for such technologies. As we know after WWII America and the Soviet Union wanted Nazi technology badly . Can you say Foo Fighters.

And so are we. How about infiltrating the military? How about placing more importance on Earth based artifacts, like the Bosnian Pyramid?

We don't want to know. THEY don't want us to know. So let's just forget it, ok? Ain't gonna happen. Not till THEY decide we are ready for "a high impact" event. What a couple of presumtuous clowns to think they can do what no one else can: Skirt the Powers That Be.

Yes its true about the religions.
But Kepler demystified the heavens some 300 years ago. Then " people looked up and seen deamons and angels in their daily lives.
It was part of who and what there society was.
they would try to propriate or appease the gods.
if they didn't know or understand something it was magic or had to be from the gods.
..
..
but in fact, have we been visited?
there is no supporting physical evidence that we have.
..
..
no one more than I would love to see it.
but cold hard facts are what we need.

To me it one of those things "you believe or you dont". I believe the "artifacts" on this planet are proof enough that we have had a more advanced "people" on this planet before. From here or not I dont know. Still around or not is a definate YES. Why would an advanced alien want to come here? For the same reason we want to go there! Knowledge, adventure, profit and fun! Most people would need only 1 of these reasons but will use all 4 if needed. Others will be afraid and never get off the ground. The doubters will wait for people to fail and then say "told you so" and live in the shadows of every one that succeeds.